Method for reducing an organic solvent remaining in tris-(2,3-epoxypropyl)-isocyanurate crystals

Abstract

A method for reducing an organic solvent remaining in tris-(2,3-epoxypropyl)-isocyanurate crystals, which comprises pulverizing crystal particles of tris-(2,3-epoxypropyl)-isocyanurate while evaporating a volatile component from the surface of the particles.

What is claimed is: 
     
       1. A method of evaporatively treating tris-(2,3-epoxypropyl)-isocyanurate crystals, comprising: pulverizing crystal particles of tris-(2,3-epoxypropyl)-isocyanurate, which have been washed with an organic solvent which effectively removes impurities from the crystals which are present therein as a result of the preparation of tris-(2,3-epoxypropyl)-isocyanurate, while evaporating said solvent and epichlorohydrin reactant from the surfaces of the particles.   
     
     
       2. The method of claim 1, wherein the pulverization with evaporation occurs in a pulverizing device under a stream of air or an inert gas passing through the pulverizer at a pressure of 1-10 kg/cm 2 , said pulverization reducing the average particle size of the crystals to 0.5-20 μm. 
     
     
       3. The method of claim 1, wherein evaporation occurs at a temperature of 100-140° C. 
     
     
       4. The method of claim 3, wherein said temperature ranges from 120-140° C. 
     
     
       5. The method of claim 2, wherein the particles of tris-(2,3-epoxypropyl)-isocyanurate placed in said pulverizing apparatus range in average particle size from greater than 20-500 μm. 
     
     
       6. The method of claim 1, wherein the concentration of organic solvent remaining in the pulverized particles is at most 300 ppm. 
     
     
       7. The method of claim 1, wherein the crystal particles of tris-(2,3-epoxypropyl)-isocyanurate are in the β-form. 
     
     
       8. The method of claim 7, wherein the crystals of tris-(2,3-epoxypropyl)-isocyanurate in β-form are prepared by reacting cyanuric acid with epichlorohydrin in the presence of a catalyst, thereby forming a chlorohydrin ester of isocyanuric acid, followed by dehydrochlorinating the chlorohydrin ester with an alkali, separating the resulting alkali metal salt thereby resulting in a reaction solution containing tris-(2,3-epoxpropyl)-isocyanurate, and then crystallizing the tris-(2,3-epoxpropyl)-isocyanurate from solution. 
     
     
       9. The method of claim 6, wherein the remaining organic solvent is epichlorohydrin. 
     
     
       10. The method of claim 1, wherein the organic solvent employed for washing of crystals of tris-(2,3-epoxypropyl)-isocyanurate is selected from the group consisting of methanol, ethanol, isopropyl alcohol, methyl ethyl ketone, acetonitrile, dimethylformamide and epichlorohydrin. 
     
     
       11. The method of claim 2, wherein said inert gas is nitrogen.